Deviant control in additive manufacturing

ABSTRACT

In one example, an additive manufacturing process includes: making an object slice by slice, including dispensing a first quantity of each of multiple liquid functional agents on to a layer of fusable build material and then irradiating the layer of build material; while making the object, identifying a deviant region in a slice; and dispensing a second quantity different from the first quantity of at least one of the functional agents into a location corresponding to the deviant region.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/236,698, filed on 21 Apr. 2021 and entitled “Deviant Control inAdditive Manufacturing,” which is a continuation of U.S. Pat. No.11,072,123, filed on 10 Aug. 2018 and entitled “Deviant Control inAdditive Manufacturing,” which is a national stage application thatclaims the benefit of and priority to international App. No.PCT/US2017/013914, filed on 18 Jan. 2017, all of which are incorporatedherein by reference in their entireties.

BACKGROUND

Additive manufacturing machines produce 3D objects by building up layersof material. Some additive manufacturing machines are commonly referredto as “3D printers.” 3D printers and other additive manufacturingmachines make it possible to convert a CAD (computer aided design) modelor other digital representation of an object into the physical object.The object model data may be processed into slices each defining thatpart of a layer or layers of build material to be formed into theobject.

DRAWINGS

FIGS. 1 and 2 are elevation and plan views, respectively, illustratingone example of an additive manufacturing machine.

FIGS. 3-18 present a sequence of elevation and plan views illustratingone example of a process for thermal control using machine 10 shown inFIGS. 1 and 2 .

FIGS. 19-21 illustrate example thermographs corresponding to the objectslice shown in FIGS. 2, 10, and 18 , respectively.

FIGS. 22-27 are flow diagrams illustrating example additivemanufacturing processes.

FIG. 28 is a block diagram illustrating one example of processorreadable medium with deviant control instructions thereon to help forman object during additive manufacturing.

FIG. 29 is a block diagram illustrating one example of an additivemanufacturing machine implementing a controller with thermal controlinstructions to help form an object during additive manufacturing.

The same part numbers designate the same or similar parts throughout thefigures. The figures are not necessarily to scale.

DESCRIPTION

In some additive manufacturing processes, heat is used to fuse togetherthe particles in a powdered build material to form a solid object. Heatto fuse the build material may be generated, for example, by applying aliquid fusing agent to a thin layer of powdered build material in apattern based on the object slice and then exposing the patterned areato fusing light. Light absorbing components in the fusing agent absorblight energy to help sinter, melt or otherwise fuse the build materialinto a slice of the object. The process is repeated layer by layer andslice by slice to complete the object. Other functional agents may beused to produce the desired characteristics of an object. For example,detailing agents may be used to enhance or inhibit fusing in certainregions of an object, coloring agents may be used for different colorobjects or different colors in a single object, and other agents may beused to affect physical properties such as ductility and conductivity.

The way in which liquid functional agents interact with one another andtheir cumulative effect on the build material during additivemanufacturing may be difficult to predict. For example, cyan, magentaand yellow coloring agents may absorb fusing light differently from oneanother, and much differently from a black fusing agent, and thuscontribute relatively more or less fusing heat. In addition, dispensingeven small quantities of any liquid agent can cool the affected workarea noticeably during manufacturing. Thus, the competing thermaleffects of each agent may influence the quality and characteristics ofthe object.

A new technique has been developed to help correctly balance the effectsof multiple liquid functional agents during additive manufacturing. Inone example, an additive manufacturing process includes, while makingthe object, measuring temperatures at multiple locations in the object,mapping any “hot” regions and any “cold” regions, and modifying theprocess control data to dispense a different quantity of at least one ofthe functional agents at the locations corresponding to each of the hotand cold regions, to reduce or eliminate the unwanted condition. Forexample, the quantity of fusing agent may be decreased at the hotregions for less heat and increased at the cold regions for more heat,to bring the temperatures into an acceptable range. Adjustments may madeand their effects measured iteratively slice by slice while making theobject or the adjustments may be made and their effects measured whenmaking the object again.

Examples are not limited to detecting and correcting temperaturedeviations. Although temperature is comparatively easy to detect “on thefly” as an indicator of meaningful object properties, other parameterscould be used. For example, it may be desirable in some implementationsto detect color, density or conductivity. Accordingly, these and otherexamples shown in the figures and described below illustrate but do notlimit the scope of the patent, which is defined in the Claims followingthis Description.

As used in this document, “and/or” means at least one of the connectedthings; “cold” and “low temperature” mean below a temperature threshold;a “coloring agent” means a substance that colors a build material; a“detailing agent” means a substance that inhibits or prevents orenhances fusing a build material, for example by modifying the effect ofa fusing agent; “deviant” means not acceptable; a “fusing agent” means asubstance that causes or helps cause a build material to sinter, melt orotherwise fuse; “hot” and “high temperature” mean above a temperaturethreshold; a “lamp” means any device that emits light; “light” meanselectromagnetic radiation of any wavelength; a “liquid” means a fluidnot composed primarily of a gas or gases; a “processor readable medium”means any non-transitory tangible medium that can embody, contain,store, or maintain instructions for use by a processor and may include,for example, circuits, integrated circuits, ASICs (application specificintegrated circuits), hard drives, random access memory (RAM), read-onlymemory (ROM), and memory cards and sticks; and “work area” means anysuitable structure to support or contain build material for fusing,including underlying layers of build material and in-process slice andother object structures.

FIGS. 1 and 2 are elevation and plan views, respectively, illustratingone example of an additive manufacturing machine 10. FIGS. 3-18 presenta sequence of elevation and plan views showing one example of a processfor thermal control using machine 10. Referring first to FIGS. 1 and 2 ,additive manufacturing machine 10 includes a first, “fuser” carriage 12and a second, “dispenser” carriage 14. Carriages 12 and 14 move back andforth, for example on rails 16, over a work area 18 at the direction ofa controller 20. Controller 20 represents the processor (or multipleprocessors), the associated memory (or multiple memories) andinstructions, and the electronic circuitry and components needed tocontrol the operative elements of machine 10.

Fuser carriage 12 carries a layering device 22, a property detector 24,and a fusing lamp 26. Dispenser carriage 14 carries an inkjet printheadassembly or other suitable liquid dispensing assembly 28 to dispensemultiple liquid functional agents. In the example shown, dispensingassembly 28 includes two dispensers 30 and 32. Each dispenser 30, 32 maydispense one or multiple functional agents, including for example, afusing agent, a detailing agent and multiple coloring agents.

Work area 18 represents any suitable structure to support or containbuild material for fusing, including underlying layers of build materialand in-process slice and other object structures. For a first layer ofbuild material, for example, work area 18 may be formed on the surfaceof a platform 34 that moves up and down to accommodate the layeringprocess. For succeeding layers of build material, for example as shownin FIG. 1 , work area 18 may be formed on an underlying object structure36, which may include unfused build material 38 and build material thathas been fused into an object slice 40.

In the example shown in FIGS. 1 and 2 , layering device 22 isimplemented as a roller 22 that moves between a deployed position (shownin FIG. 1 ) to layer build material as carriage 12 moves over work area18 and a retracted position (shown in FIG. 5 ) to not layer buildmaterial as carriage 12 moves over work area 18. Layering roller 22 mayrotate freely as it is moved over work area 18, freewheeling clockwiseor counter-clockwise depending on the direction of travel, or roller 22may be driven rotationally in either direction (co-rotated orcounter-rotated). Other implementations for a layering device 22 arepossible including, for example, a blade or a device that dispensesbuild material directly over the work area in a layer.

In the example shown in FIGS. 1 and 2 , property detector 24 isimplemented as a thermal imaging device 24, such as an infrared cameraor other suitable device for measuring temperatures in an object slice40. Temperature measurements from device 24 are mapped to thecorresponding locations in slice 40 to form a thermal map of the slice.Depending on the capabilities of the thermal imaging device 24,temperature mapping may be performed by device 24 and mapping datatransmitted to controller 20 for processing, or temperature mapping maybe performed by controller 20. One example of a temperature map 41 forobject slice 40 in FIGS. 1 and 2 is shown in FIG. 19 . To representtemperature on a black and white line drawing, “isotemp” lines are usedto show different temperature regions. Higher temperature regions in theobject slice are depicted by more dense groupings of lines and lowertemperature regions are depicted by less dense groupings of lines. Map41 shows a hot region 42 near the center of slice 40 and a cold region44 along one edge of slice 40.

Although a single fusing lamp 26 is depicted, multiple fusing lamps maybe used, for example to enable a greater range of fusing light.

In FIGS. 1 and 2 , fuser carriage 12 is parked on one side of work area18 (the left side in FIGS. 1 and 2 ) and dispenser carriage 14 is parkedon the other side of work area 18 (the right side in FIGS. 1 and 2 ). Inthis example, a ribbon 46 of build material powder 38 has been depositedalong a left side deck 48 adjacent to work area 18. In FIGS. 3 and 4 ,fuser carriage 12 is moving to the right in a first pass, indicated bymotion arrows 50, with roller 22 deployed to layer build material 38 ina layer 52 over work area 18 (underlying structure 36). Although apowdered build material 38 is depicted by stippling in the figures, anysuitable fusable build material may be used.

In FIGS. 5 and 6 , fuser carriage 12 and dispenser carriage 14 aremoving to the left in a second pass, indicated by motion arrows 56, withlayering roller 22 retracted and fusing lamp 26 turned on to pre-heatbuild material 38 in layer 52. In other examples, build material 38 isnot pre-heated or it is pre-heated with a heating lamp separate from thefusing lamp. Other pre-heating configurations are possible.

Still referring to FIGS. 5 and 6 , dispenser 30 on dispenser carriage 14following fuser carriage 12 dispenses a fusing agent 58 on to buildmaterial 38 in layer 52 in a pattern 60 corresponding to the desiredobject slice. For example, a lesser quantity of fusing agent 58 may bedispensed at the location of hot region 42 in slice 40 to lower thetemperature in the corresponding region of the new slice and a greaterquantity of fusing agent 58 may be dispensed at the location of coldregion 44 in slice 40 to raise the temperature in the correspondingregion in the new slice. Although only a fusing agent 58 is shown, otherfunctional agents may be dispensed from one or both dispensers 30, 32 onto build material 38 as dispenser carriage 14 is moved to the left overwork area 18 in FIGS. 5 and 6 .

In FIGS. 7 and 8 , as dispenser carriage 14 is moved to the right in athird pass, indicated by motion arrows 62, dispenser 32 dispenses acoloring agent 64 on to build material 38 in layer 52. Although only acoloring agent 64 is shown, other functional agents may be dispensedfrom one or both dispensers 30, 32 on to build material 38 as dispensercarriage 14 is moved to the right over work area 18 in FIGS. 7 and 8 .Also in this third pass, fuser carriage 12 follows dispenser carriage 14over work area 18 with fusing lamp 26 turned on to irradiate patternedbuild material 60 with fusing light to fuse patterned build materialinto a second object slice 66. Thermal imaging device 24 is turned on tomeasure temperatures in slice 66.

In FIGS. 9 and 10 , fuser carriage 12 and dispenser carriage 14 havereached the right side of work area 18 after forming second slice 66 anda ribbon 46 of build material 38 has been dispensed to supply deck 48 onthe right side of work area 18 in preparation for making the next slice.One example of a thermal map 67 for object slice 66 in FIGS. 9 and 10 isshown in FIG. 20 . Although map 67 shows a hot region 68 near the centerof slice 66 and a cold region 70 along one edge of slice 66. However,the lesser quantity of fusing agent 58 dispensed at the location of hotregion 42 in the preceding slice 40 has lowered the temperature in thecorresponding region 68 of the new slice 66, as indicated by the lessdense isotemp lines in region 68, and a greater quantity of fusing agent58 dispensed at the location of cold region 44 in the preceding slice 40has raised the temperature in the corresponding region 70 in the newslice 66, as indicated by the more dense isotemp lines in region 70.

The sequence of operations is repeated for the next slice, as shown inFIGS. 11-18 . In FIGS. 11-12 and 13-14 , fuser carriage 12 and dispensercarriage 14 are moving to the left in a first pass, indicated by motionarrows 56. In FIGS. 11 and 12 , roller 22 is deployed to layer buildmaterial 38 in a next layer 74 over work area 18 (now underlyingstructure 76) and fusing lamp 26 is turned on to pre-heat build material38 in layer 74. In FIGS. 13 and 14 , as carriages 12, and 14 continueacross work area 18, dispenser 30 dispenses a fusing agent 58 on tobuild material in layer 74 in a pattern 78 corresponding to the nextobject slice. For example, a lesser quantity of fusing agent 58 may bedispensed at the location of hot region 68 in slice 66 to lower thetemperature in the corresponding region of the new slice and a greaterquantity of fusing agent 58 may be dispensed at the location of coldregion 70 in slice 66 to raise the temperature in the correspondingregion in the new slice. Although only a fusing agent 58 is shown, otherfunctional agents may be dispensed from one or both dispensers 30, 32 onto build material layer 74 as dispenser carriage 14 is moved to the leftover work area 18 in FIGS. 13 and 14 .

In FIGS. 15 and 16 , as dispenser carriage 14 moves to the right in asecond pass, indicated by motion arrows 62, dispenser 32 dispenses acoloring agent 64 on to build material in layer 74. Although only acoloring agent 64 is shown, other functional agents may be dispensedfrom one or both dispensers 30, 32 on to build material layer 74 asdispenser carriage 14 is moved to the right over work area 18 in FIGS.15 and 16 . Also in this second pass, fuser carriage 12 followsdispenser carriage 14 over work area 18 with fusing lamp 26 turned on toirradiate patterned build material 78 with fusing light to fusepatterned build material into a third object slice 80. Thermal imagingdevice 24 is turned on to measure temperatures in slice 80.

In FIGS. 17 and 18 , fuser carriage 12 and dispenser carriage 14 havereached the right side of work area 18 after forming third slice 80. Oneexample of a thermal map 81 for object slice 80 in FIGS. 17 and 18 isshown in FIG. 21 . In map 81 there are no hot or cold regions.

The sequence of operations may continue for each succeeding layer ofbuild material, slice by slice, until the object is completed.

The configuration and operating sequence of machine 10 in FIGS. 1-18 isjust one example. Other suitable machine configurations and otheroperating sequences are possible. For example, an additive manufacturingmachine 10 may include more or fewer carriages that move in-line withone another or perpendicular to one another, and with more or feweragent dispensers, lamps and thermal imaging devices.

FIG. 22 illustrates one example of an additive manufacturing process100, such as might be implemented with a machine 10 shown in FIGS. 1 and2 . Referring to FIG. 22 , an object is made slice by slice at block101, including dispensing a first quantity of each of multiple liquidfunctional agents on to a layer of fusable build material and thenirradiating the layer of build material, for example as shown in thesequence of operations illustrated in FIGS. 1-18 . A deviant region in aslice is identified while making the object, at block 102, for exampleby identifying a hot region 42 and/or a cold region 44 on a temperaturemap in FIG. 19 . And then, at block 103, a second quantity differentfrom the first quantity of at least one of the functional agents isdispensed into a location corresponding to the deviant region, forexample by dispensing a greater or lesser quantity of a fusing agent 58as shown in FIGS. 5 and 13 , and/or a lesser quantity or a greaterquantity of a coloring agent 64, as shown in FIGS. 7 and 15 .

Dispensing a different quantity of one or more of the functional agentsat block 103 in process 100 may be implemented by making the adjustmentin the next slice of the same object, as shown at block 104 in FIG. 23 ,or by making the adjustment in the next object, as shown at block 105 inFIG. 24 , or a combination of both succeeding slice and succeedingobject adjustments.

Blocks 102 and 103 in process 100 may be implemented for a group ofmultiple slices rather than for individual slices. For example, it maybe desirable in some manufacturing operations to measure and map thetemperatures in every 2nd or 3rd or 4th slice as a sufficiently accurateindicator of the temperatures in each of the individual slices in thegroup, and then adjusting the quantity of agent(s) to correct anytemperature deviant regions in the succeeding 2nd or 3rd or 4th sliceand/or in the corresponding group of slices when making the next object.

FIG. 25 illustrates another example of an additive manufacturing process110, such as might be implemented with a machine 10 shown in FIGS. 1 and2 . Referring to FIG. 25 , process 110 includes making a slice of anobject based on process control data, including dispensing a quantity ofeach of multiple liquid functional agents on to a layer of fusable buildmaterial according to the process control data and then irradiating thelayer of build material (block 111), and determining if there is a hotregion in the slice (block 112). If it is determined there is a hotregion in the slice, then modifying the process control data to dispensea different quantity of at least one of the functional agents at alocation corresponding to each hot region to cool the slice at thatlocation (block 113). Process 110 also includes determining if there isa cold region in the slice (block 114) and, if it is determined there isa cold region in the slice, then modifying the process control data todispense a different quantity of at least one of the functional agentsat the location of each cold region to heat the slice at that location(block 115). The acts of making (block 111), determining (blocks 112 and114), and modifying (blocks 113 and 115) are repeated for succeedingslices until it is determined that there are no hot regions and no coldregions (block 116). The object can then be made again (and repeatedly)according to the last modified process control data.

FIG. 26 illustrates another example of an additive manufacturing process120, such as might be implemented with a machine 10 shown in FIGS. 1 and2 . Referring to FIG. 26 , process 120 includes making an object basedon process control data, including dispensing a quantity of each ofmultiple liquid functional agents on to a fusable build material in apattern to form patterned build material and to irradiate the patternedbuild material (block 121) and, while making the object, measuringtemperatures at multiple locations in the object (block 122). Process120 also includes mapping the measured temperatures to form atemperature map of the object (block 123), modifying the process controldata based on the temperature map (block 124) and then making the objectagain based on the modified process control data, including dispensing adifferent quantity of at least one of the functional agents on to thebuild material (block 125). Process control data for a group of multipleslices may be modified based on a temperature map for each of theindividual slices in the group.

FIG. 27 illustrates another example of an additive manufacturing process130, such as might be implemented with a machine 10 shown in FIGS. 1 and2 . Referring to FIG. 27 , process 130 includes layering build materialover a work area (block 131), dispensing a first quantity of each of thefusing agent and a coloring agent on to a layer of build material in apattern corresponding to an object slice (block 132), and irradiatingthe patterned build material to fuse build material into the slice(block 133). Process 130 also includes mapping temperatures in the slice(block 134), identifying any regions of low temperature in the slice andany regions of high temperature in the slice (block 135), and repeatingthe sequence of layering, dispensing, irradiating, mapping andidentifying for multiple successive layers of build material to make theobject (block 136) and then making the object again layer by layer andslice by slice including dispensing a second quantity different from thefirst quantity of the fusing agent and/or the coloring agent into theregions of low temperature and into the regions of high temperature(block 137).

FIG. 28 is a block diagram illustrating a processor readable medium 82with deviant control instructions 84 to help manufacture an object. Forone example, instructions 84 may include instructions to execute process100 in FIG. 22 . For other examples, instructions 84 may includeinstructions to execute process 110 in FIG. 25 , process 120 in FIG. 26, or process 130 in FIG. 27 .

Processor readable medium 82 with deviant control instructions 84 may beimplemented, for example, in a CAD computer program product, in anobject model processor, and/or in a controller for an additivemanufacturing machine. Process control data to adjust the quantity offusing agents, color agents and/or other liquid functional agents may begenerated “on the fly”, for example, by processor readable instructionsexecuted on the additive manufacturing machine controller.

FIG. 29 is a block diagram illustrating one example of an additivemanufacturing machine 10 implementing a controller 20 with deviantcontrol instructions 84. In this example, deviant control instructions84 include instructions to control thermal deviations, for example asshown in FIGS. 1-18 and 25-27 . Referring to FIG. 29 , machine 10includes controller 22, a work area 18, a build material layering device22, a first fusing or other functional agent dispenser 30, a secondcoloring or other functional agent dispenser 32, a thermal imagingdevice 24 and a fusing lamp 26. Build material layering device 22 layersbuild material over work area 18 and may include, for example, a deviceto dispense the build material and a blade, brush or roller to spreadthe build material for each layer. Agent dispensers 30 and 32 dispenserespective agents selectively at the direction of controller 20, forexample as described above with reference to FIGS. 5, 7, 13 and 15 .While any suitable dispensers 30, 32 may be used, inkjet printheads aresometimes used in additive manufacturing machines because of theprecision with which they can dispense fusing, detailing, coloring andother functional agents and their flexibility to dispense differenttypes and formulations of such agents.

As noted above, controller 20 represents the processor (or multipleprocessors), the associated memory (or multiple memories) andinstructions, and the electronic circuitry and components needed tocontrol the operative elements of machine 10. In particular, controller20 includes a processor readable medium 82 with thermal controlinstructions 84 and a processor 86 to read and execute instructions 84.Thermal imaging device 24 may be implemented as an infrared camera orother suitable device for measuring temperatures in an object slice.Temperature measurements from device 24 may be mapped to thecorresponding locations in the slice to form a thermal map of the slice.Depending on the capabilities of the thermal imaging device 24,temperature mapping may be performed by device 24 and mapping datatransmitted to controller 20 for processing and/or temperature mappingmay be performed by controller 20.

In one example, an additive manufacturing process includes: making anobject slice by slice, including dispensing a first quantity of each ofmultiple liquid functional agents on to a layer of fusable buildmaterial and then irradiating the layer of build material; while makingthe object, identifying a deviant region in a slice; and dispensing asecond quantity different from the first quantity of at least one of thefunctional agents into a location corresponding to the deviant region.

In one example, the process described may include, while making theobject, measuring a material property of each slice or group of slicesin the object and where identifying a deviant region in a slice includesidentifying a deviant region from the property measurements.

In one example, measuring a material property in the process may includemeasuring a temperature of each slice or group of slices in the object.

In one example, the process may include dispensing a second quantitydifferent from the first quantity of at least one of the functionalagents into a location corresponding to the deviant region includesdispensing a second quantity different from the first quantity of atleast one of the functional agents into a location in the next slicecorresponding to the deviant region.

In one example, the process may include identifying a deviant region inthe object includes identifying regions of low temperature in the objectand regions of high temperature in the object, and dispensing a secondquantity different from the first quantity of at least one of thefunctional agents into a location corresponding to the deviant regionincludes dispensing a second quantity different from the first quantityof at least one of the functional agents into locations corresponding tothe regions of low temperature and the regions of high temperature.

In one example, the process may include making the object includesdispensing a fusing agent and multiple coloring agents each having adifferent light absorbability, and dispensing a second quantitydifferent from the first quantity of at least one of the functionalagents into a location corresponding to the deviant region includesdispensing a second quantity different from the first quantity of thefusing agent and/or at least one of the coloring agents into locationscorresponding to the regions of low temperature and into locationscorresponding to the regions of high temperature.

In one example, the process may include dispensing a second quantitydifferent from the first quantity of at least one of the functionalagents into a location corresponding to the deviant region includesdispensing a second quantity greater than the first quantity of thefusing agent into each location corresponding to a region of lowtemperature and dispensing a second quantity lesser than the firstquantity of the fusing agent into each location corresponding to aregion of high temperature.

In one example, the process may include a second quantity different fromthe first quantity of at least one of the functional agents into alocation corresponding to the deviant region includes making the objectagain slice by slice including dispensing a second quantity differentfrom the first quantity of at least one of the functional agents into alocation corresponding to the deviant region.

In one example, the process may include identifying a deviant region inthe object includes identifying regions of low temperature in the objectand regions of high temperature in the object and making the objectagain slice by slice includes dispensing a second quantity differentfrom the first quantity of at least one of the functional agents intolocations corresponding to the regions of low temperature and theregions of high temperature.

In one example, the process may include making the object includesdispensing a fusing agent and multiple coloring agents each having adifferent light absorbability and making the object again includesdispensing a second quantity different from the first quantity of thefusing agent and/or at least one of the coloring agents into locationscorresponding to the regions of low temperature and into locationscorresponding to the regions of high temperature.

In one example, the process may include making the object again includesdispensing a second quantity greater than the first quantity of thefusing agent into each location corresponding to a region of lowtemperature and dispensing a second quantity lesser than the firstquantity of the fusing agent into each location corresponding to aregion of high temperature.

As noted above, the examples shown in the figures and described hereinillustrate but do not limit the scope of the patent, which is defined inthe following Claims.

“A”, “an” and “the” used in the claims means at least one. For example,“a” deviant region means at least one deviant region and “the” deviantregion means the at least one deviant region.

What is claimed is:
 1. An additive manufacturing process, comprising:making a slice of an object based on process control data, includingdispensing a quantity of a functional agent on to a layer of fusablebuild material according to the process control data and thenirradiating the layer of build material; determining there is a hotregion in the slice; in response to determining there is a hot region inthe slice, modifying the process control data to dispense a differentquantity of the functional agent at a location corresponding to each hotregion to cool the slice at that location; determining there is a coldregion in the slice; in response to determining there is a cold regionin the slice, modifying the process control data to dispense a differentquantity of the functional agent at the location of each cold region toheat the slice at that location; repeating the making, determining, andmodifying for succeeding slices until determining there are no hotregions and no cold regions; and continue making object slices based ona last modified process control data until the object is completed. 2.The process of claim 1, comprising making the object again according tothe last modified process control data.
 3. The process of claim 1, wherethe functional agent has a specific light absorbability.
 4. The processof claim 1, wherein the different quantity of the functional agent to bedispensed at the location of each cold region to heat the slice at thatlocation comprises a greater quantity of the functional agent thanpreviously dispensed.
 5. The process of claim 1, wherein the differentquantity of the functional agent to be dispensed at the location of eachhot region to cool the slice at that location comprises a lesserquantity of the functional agent than previously dispensed.
 6. Theprocess of claim 1, wherein the different quantity of the functionalagent to be dispensed at the location of each cold region to heat theslice at that location is a greater quantity that increases thetemperature of the location in the slice and in one or more of thesucceeding slices.
 7. The process of claim 1, wherein the differentquantity of the functional agent to be dispensed at the location of eachhot region to cool the slice at that location is a lesser quantity thatdecreases the temperature of the location in the slice and in one ormore of the succeeding slices.
 8. A processor readable medium havinginstructions thereon that when executed cause an additive manufacturingmachine to perform a method, the medium comprising: make a slice of anobject based on process control data, including dispensing a quantity ofa functional agent on to a layer of fusable build material according tothe process control data and then irradiating the layer of buildmaterial; determine there is a hot region in the slice; in response to adetermination there is a hot region in the slice, modify the processcontrol data to dispense a different quantity of the functional agent ata location corresponding to each hot region to cool the slice at thatlocation; determine there is a cold region in the slice; in response toa determination there is a cold region in the slice, modify the processcontrol data to dispense a different quantity of the functional agent atthe location of each cold region to heat the slice at that location;repeat the making, determining, and modifying for succeeding slicesuntil it is determined that there are no hot regions and no coldregions; and continue to make object slices based on a last modifiedprocess control data until the object is completed.
 9. The medium ofclaim 8, having instructions to make the object again according to thelast modified process control data.
 11. The medium of claim 8, whereinthe instructions further cause the additive manufacturing machine to:determine whether a temperature of the location is below a coldtemperature threshold or above a hot temperature threshold.
 12. Themedium of claim 8, wherein the instructions further cause the additivemanufacturing machine to: based on modifying the process control data todispense a different quantity of the functional agent at a locationcorresponding to each hot region, dispense a lesser quantity of thefunctional agent to cool the slice at that location.
 13. The medium ofclaim 8, wherein the instructions further cause the additivemanufacturing machine to: based on modifying the process control data todispense a different quantity of the functional agent at the location ofeach cold region, dispense a greater quantity of the functional agent toheat the slice at that location.
 14. An additive manufacturing machinecontroller implementing the processor readable medium of claim
 8. 15. Anadditive manufacturing machine, comprising: a layering device to layerbuild material over a work area; an agent dispenser to dispense afunctional agent on to layered build material; a fusing lamp toirradiate patterned build material; a thermal imaging device to maptemperatures in fused build material; and a controller operativelyconnected to the layering device, the agent dispenser, the fusing lampand the thermal imaging device, the controller including a processor anda processor readable medium having instructions thereon that whenexecuted by the processor cause the machine to: make a slice of anobject based on process control data, including to dispense a quantityof the functional agent on to a layer of fusable build materialaccording to the process control data and then irradiating the layer ofbuild material; determine there is a hot region in the slice; inresponse to determining there is a hot region in the slice, modify theprocess control data to dispense a different quantity of the functionalagent at a location corresponding to each hot region to cool the sliceat that location; repeat the making, determining, and modifying forsucceeding slices until determining there are no hot regions; andcontinue making object slices based on a last modified process controldata until the object is completed.
 16. The machine of claim 15, whereinto determine there is a hot region in the slice, the instructionsinclude instructions to: determine a temperature of the location isabove a temperature threshold.
 17. The machine of claim 15, wherein theinstructions include instructions to: determine there is a cold regionin the slice; in response to determining there is a cold region in theslice, modify the process control data to dispense a different quantityof the functional agent at the location of each cold region to heat theslice at that location; repeat the making, determining, and modifyingfor succeeding slices until determining there are no cold regions; andcontinue making object slices based on a last modified process controldata until the object is completed.
 18. The machine of claim 17, whereinto determine there is a cold region in the slice, the instructionsinclude instructions to: determine a temperature of the location isbelow a temperature threshold.
 19. The machine of claim 15, wherein theinstructions include instructions to: repeat the making, determining,and modifying for a group of succeeding slices until it is determinedthat there are no hot regions and no cold regions.
 20. The machine ofclaim 15, wherein the instructions include instructions to: repeat themaking, determining, and modifying for each slice in the succeedingslices until it is determined that there are no hot regions and no coldregions.